While the article mentions Amdahl's Law, it is outdated, as described at http://www.cis.temple.edu/~shi/docs/amdahl/amdahl.html
AMD taster than Intel, but only under Linux!!!
Hmmm, one more reason to go Linux.
my bet here is that the poor performance in windows is due to hypertransport and the way cores are interconnected internally but is not AMD faults at the end is intel's/microsoft faults.
my bet is that somehow microsoft have some internal optimization in their thread api that force it to assume or add latency to compensate the heat produced for the old fsb system from intel, so that could ovbiuosly kill the benefit of Athlon/phenom/opteron hypertransport and inner memory manager due to the self generated latency.
now on the other hand could simple be that microsoft and intel have some hidden deal in there to slowdown amd chips internally so they make sure amd wont kill they processor in benchys by much, pretty much like the famous microsft/foxxcon bios "misunderstanding" from the g33 chipsets
(although I don't know which toolchain built the Blender Windows
binaries in the AT test linked to above).
Here's an interesting evaluation of compilers. It's 3 years old
but still highly entertaining (at least to me):
AMD invented the x86-64 mode.
Conroe (core 2)'s 64-bit implementation is still a little bit hackish.
Try adding Nehalem Xeons to the comparison, it truces AMD in no matter how many bits computing mode.